Check.Church

Church of the East

The Church of the East grew up in Persia, administratively independent from 424 and, after the Council of Ephesus in 431, formally aligned in 484 with the theology that council had condemned. Its heirs are the Assyrian and Ancient Churches of the East and, through the union of 1552, the Chaldean Catholic Church.

On the tree

The Church of the East family and the bodies it separated from or was organized out ofAD 33today100424431451105415521968The post-apostolic church (The spine)The post-apostolicchurchThe spineChurch of the East (Church of the East)Church of the EastChurch of the EastThe conciliar church (The spine)The conciliar churchThe spineThe Chalcedonian church (The spine)The Chalcedonian churchThe spineRoman Catholicism (Catholic)Roman CatholicismCatholicChaldean Catholic Church (Church of the East)Chaldean Catholic ChurchChurch of the EastAncient Church of the East (Church of the East)Ancient Church of theEastChurch of the East

Solid lines are separations and unions; dashed lines are renewals that began inside a body; dotted gray lines are national organizations of one communion; a diamond marks a fork event where neither side is drawn as the one that left. Every line runs back to the post-apostolic church; no body descends from the assembly of Acts 2.

Bodies in this family

  1. Church of the East424–484

    The church in Persia, administratively independent since 424 to deflect charges of Roman allegiance, did not receive the Council of Ephesus (431) and formally aligned with the dyophysite school in 484. 'Nestorian' is an exonym the tradition rejects. A 1994 joint declaration with Rome confessed a common faith in the Incarnation.

  2. Chaldean Catholic Church1552–1830

    Born of a revolt against hereditary patriarchal succession, resolved by union with Rome — though the Catholic and traditionalist identities of the rival lines crossed and re-crossed for two centuries before settling into today's Chaldean Catholic Church and Assyrian Church of the East; now the church of the majority of Iraqi Christians.

  3. Ancient Church of the East1968

    The 1968 traditionalist division of the Assyrian church over the 1964 calendar and liturgical reforms and the patriarch's absentee governance — a modern echo, as the sources themselves note, of the two-rival-lines pattern of 1552.

Claimed lineage

What this tradition says about its own origin · apostolic see

The Church of the East traces its founding to the Apostle Thomas and to Addai and Mari of the Seventy (Edessa/Seleucia-Ctesiphon tradition); its anaphora of Addai and Mari is among the oldest in continuous use.

Its own sources: Liturgy of Saints Addai and Mari; Doctrine of Addai (tradition).

The documented record for this claim is being cited and will follow.

Research compiled July 2026. Page data built 2026-10-10.